Method and apparatus  fos the manufacture op glass plates



Nav, ll, 1924.

F. L.. o. wADswoRTH- METHOD AND APPARATUS FOR THE MANUFACTUREIIOF GLASS PLATES FIG. 'I

INVENTOR 200. www# Nw, ll, 1924.

F.L.O.WADSWORTH METHOD AND APPARATUS FOR THE MANUFACTURE OF AGLASS PLATES INvEn-ron f fmt/amvb 6 Sheets-Sheet 2 led Nov. l N

1,515,450 F. L.. O. WADSWORTH METHOD AND APPARATUS FOR THE MANUEACTURE oF GLASS PLATES Nav, ll, 1924.

Nov, ll, 1924 1,515,450

. F. L. O, WADSWORTH METHOD AND APPARATUS FOR THE MANUTACTURE 0T GLAss PLATES Ni, 1l, 1924.

F Lf. WADSWORTH METHOD AND APPARATUS 'FOR THE MANUFACTURE oF GLAss PLATES Filed Nov. 2b, 1918 s sheetssheet 5 Nov, 11, 1924. v i

F. L. O, WADSWORTH 4METHOD AND APPARATUS FOR THE MANUFACTURE OF GLASS PLATES Filed Nov. 29, 191J 6 Sheets-Sheet 6 E :R EN

INVENTOR Patented Nov. l1, 1924.

iria

PATENT FFICE.

FRANK. L. O. WADSWORTH, OF TTSBURGH, PENNSYLVANIA.

METHOD AND APLARATUS FOR THE MANUFACTURE OF (Eifiifii PLATES.

Application filed November 29, 1918.

which the :following a specification.

My .invention relates tothe manufacture ot' plate glass and sheet glass of various kinder and it is applicable broadly to the torniation oi products of this. character which have either plain or figured surfaces,

and which are produced either hy the ordinary one etep rolling' procese, or oy the two utep rolling-pressing method disclosed in applieainto` earlier Potente Noe. (3617025, t27',-/l-ti=lt 8445185) 952,39@ etc., or hy the three step rolling-heatiugpreeeinp; proeedine die closed in my eopending application Ser. No 802,3l1, `ot which this application is,V in part a continuation. The objects oi' my present invention, generally Stated, are to avoid' vor rione clitileulties due 'to the tlierinal errpansion and distortion of the table Surfaces upon which the glass sheete ere formed", to im prove the quality ot the iroduet hy providing more favorable conditions both for its initial tormationaud for its subsequentv anneali und to greatly facilitate and expedite the speed. ot operationwi. eA|` to greatly iiierease the nuinlier ot elfteete proier hour hy one ran oi nien and to pendii y reduce the com; of inanufa o t r ther 1ere epecitte Aohjecte and adieu jee ot' rey invention will he apparentcv t the art from the detail 'epatite embodiments; ofiE my .hul-infere- Inente-v-which relate in part toa proeeee-or Inode o'if proccfjlure and in part to nieane and inetifunientalitiee tor carrying out that. proeeoS---are fully explained.

ln order to facilitate an iuifgl'erstanding of 'the salient tot res of the hereinafter descrihed method for the. manufacture of Sheet or plate glass products I will tiret lirietly reifer to the manner in which these prodsfacte have heretofore been made either hy rolling; alone or hy first rolling and their metering, In these operations a mass ot uniformed molten materialf-Varying in amount trom a few hundred to several thousand ponerle` aerei-ding to the Size and thickness s Plates, of

Serial No. GQWSG.

i upper surface of the metal Support is iutensely heated by Contact with this great. mass of Very hot material the heatiugl being greateet, of course, at the end Where the molten mass is teeniedy and least et 'the end where the spreading of the Sheet ie cour pletcd. This intense heatingk of the upper surface of the `metal rolling; table r: ndlr expands' that of the 'table-us ap` preciable time is required for the heat to distribute and equalireitoelf throughout the mass ot relatively cold iron conuprieino the support-' alid ae e result of this` tepid lo calized heating; the tahle hows up or aesunies an assynnnetrical convex foon, the

bewind ofthe tehle introduces particular difficulties when the rolled sheet of glass is to he subjected to a suheequent prees o; operation; and in euch Sonie epecioli'iro- Visioninust he made to overcome these ditllcultiea Sueh, for example., ae the procedure und means disclosed in int' ornier llal'eut No.. or euch ae described in my pending; application Ser. No. E/L31 in all cages this bowing 4oit the olfjectionahle end digadtfonta 'couts it necessarily iiNet-:ci Stretching of upper layers of metah with opening;` oit the cfporee ot' the iron, Whirl alloue the escape of and ret-nits in t formation of a rough pitted or cloudedL table surface on the under eide of the glass; Sheet. At times this bowing action hecomee so pronounced as to open up crache or cheeks in the tehle supportparticularly when the ietal frein which it inode is notti/'ery homogeneous or uniform in ter;- ture-and this checking ot the iron will in time necessitate either the resurfacing oi, the entire talole or ite rejection and replacement. This difficulty is particularly Serious one in the manufacture oil. ornamental or patterned sheets et gleee--eueli tor erqzuuple.J ai rolled Sheet prieni gloss-which hy the noe et a revereel'y figured rel lOl)

The assymmetrical swelling up or crowning of the supporting surface causes the glass sheet, which has been rolled out thereon, to assume a correspondingly bent or bowed form. This sheet must be allowed to remain on the table sufficiently long to impart to it a partial set-, which will permit it to be shoved or pushed ofi' from the table, either endwise or sidewise, into an annealing lehr or oven. As it is always desirable to produce sheets which are as flat and smooth as possible the oven floors of these annealing chambers or lehrs are carefully leveled. lf the sheet is bent or warped when it leaves the rolling table it will not, at first, rest evenly on 'the flat floors of the annealing chambers; and in the movement of the sheet over the 'Hoor surfaces the contacting portions of the sheet and the floor are both subjected to local abrasion and wear. If the sheets are badly bent and set in their bent forme-as is frequently the case .in producingl rolled-pressed products of considerable thickness (such as heavy skylight prism)a considerably longer time is also required to properly straighten and anneal them in the lehr chambers, than is necessary with initially flat plates.

For all of the above reasons itis essential to reduce the bowing or crowning of the rolling table surface to a minimum. Tn the commercial manufacture of sheets in the manner above described, this action is cumulative in effect; and the only way in which it can be kept within bounds is to allow a considerable interval to elapse between the removal of one sheet from the table and the rolling of another thereon-thereby allowing a partial equalization or distribution of the heat, locally imparted to the upper surface, throughout the mass of the table and its support. But the time that can be allowed for this equalizing action is limited when only one table is used-by commercial considerations of economy, and by the fact that the surface temperature of the rolling table must not be allowed to vary by too great a range; if it is too hot the glass will stick to it, and if it is too cold the glass will be cracked or crazed on its lower side. In some cases the natural cooling of the heated table surface, in the intervals between the rolling operations, is accelerated, externally by blasts of cold air, or internally by water cooling. But any artificial chilling of the metal in this manner has been found objectionable in that it accentuates rapid changes in temperature between different portions of the table and therefore aggravates, rather than reduces, the assymmetrical distortion, and the supercial stretching and checking of the rolling surface.

The possible speed of manufacture of the sheets may be considerably increased-i. e.,

the intervals between the spreading` of successive sheets on the rolling` table may be reduced-by the use of water cooled tables; but aside from the disadvantages already mentioned such tables are only effective in accelerating production to a limited degree, because in the system of procedure heretofore employed in this line of manufacture all of the sheets produced on a single rolling table are shoved in succession into one lehr, or one system of lehr chambers; and it is necessary to leave each sheet a certain minimum length of time in each lehr station-in order to secure the necessary and essential annealing action-before it can be advanced or shoved on to the next station. This minimum interval of rest in the annealing ovens determines the maximum speed of operation in the successive rolling of the sheets; and this minimum wait period is several times the period required for the rolling or spreading operation itself. The men of` the rolling gang are therefore in some cases idle or unoccupied for more than 80% of their time.

In the improved mode of procedure employed by me the difficulties and delays heretofore encountered in sheet manufact-ure are largely avoided, or completely eliminated, by using a. twin or Janus faced rolling table-which is mounted so that it can be readily reversed or inverted between successive rolling operations-and by alternately spreading the sheets of molten glass in opposite directions and on the opposite sides of the reversible table; so that the two faces and the two ends thereof are exposed in reciprocating order to the heating and distorting effects of the hot unformed masses of glass and of the sheets or plates formed therefrom. The result of this mode of procedure is that, as the upper face of the table is expanded and stretched and bowed up ward by the heat of one sheet forming operation, the lower or opposite face is bowed or bent in the reverse direction-ewith a con` sequent slight condensation or compression of the metal on this sideand when the' table is reversed for the next operation this concaved relatively cool and condensed metal face is brought uppermost to receive the next charge of glass, which is tesmed or poured on the end opposite that which received the preceding charge, and is rolled or spread in the reverse direction. This alternate heating of opposite sides of the rolling table-with the greatest heat applied in reciprocating order to opposite ends of the said table-results in the maintenance of substantial uniformity in the average temperature conditions at different parts of the rolling table and its associated parts, and in the consequent elimination, in large part, of the effects of assymmetrical thermal distortion of the rolling surfaces. But there is a Al'iufther very marked advantage in` this reciprocating-reversed order et successi'veliy7 depositing and spreading the molten glass masses alternately on opposite ends and op- ).iusite sides of a single rolling table; and that is the possibility et effectively Water cooling the interior or center portion ot the said table-thereby increasingthe rate oi cooling of both rolling surfaces Without accentuating, but on. the contrary, reducingfr the ditl'erences ot temperature between the opposing and alternately uppermost faces thereof. This permits` of they formation of successive sheets in more rapid alternation and correspondingly increases the output otl each table and rolling gang.

In order to` avail myself fully ot the gain in speed thus effected in the rolling operas tions-and avoid the Wait necessary for the rest period in the subsequent annealing of each sheet-I als@ provide for the transter ot' successive sheets in regular sequence or order to a plurality (twoior more) of lehrs, which may be arranged in such` combined relation to the reversible rolling table that each lehr receives an additional` sheet at regular time intervals-Which are longer than the intervals between the rollingfoperations in theratio of the number otlehrs in the system-or which may also be so arranged that one olf the said lehrs receives sheets at considerably longer or shorter intervals than the other lehr 10rlehrs; this lastA arrangement and order of procedure being utilized' when it is desired to produce successive sheets of diti'enent thickness, or didenent surface configuration, Which require different rest periods inthe annealing operations. This last possibility is an important advantage inproducing limited amounts of pressed plate products in conjunction With larger quantities of ordi nary rolled sheet products; and it consti.- tutes an import-ant'V subsidiary advantage ot my present improvements.

,.t'nether feature of my reversibletable--v multiple lehr system is the arrangement of the et forming and annealinginstrument tics in such manner that each sheet can he moved from the table intethe lehrin the 'reverse direction to that in which it' is rolled out on the table, so that the end ot thc plate which is-frst formedy from. the plastic mass of glass--which is known` in shop parlance as the cold end or the black endis at the hack or hottest portion ot the oven chambers, Where it Will receive the most heat and willy be mostl cited tively softened and annealed in its passage to the lehr rods. This arrangement is particularly effective and advantageousin the utili/ation` ot' a plurality of lehrs to receive the product from my hit'aciahhidireetional rollingil apparatus, because it supplements and carries forward the favorable conditions :for temperati'lre equalization that are inaugurated?, in thel rolling operation itselfl..

by the maintcmuice el" equitable temperature cimditions in the rolling table surfaces.

With this prolimmary statement oli the general process leatures of my present. in-

many details ot actual construction (which can be readily supplied by any ceramic engineer), have heen emitted` from the relatively small scale illustrations merely for the saltey oit. avoiding unnecessary complexity and bringing out more clearly the essential mechanical features of the Working parts.

In the drawings Fig. l is agenenalsemiidiagrammatic plan view et one illustuatiac arrangen'ient et a reversible table, hidircc tional rolling apparatus` and multiple lelir system; Fig. Q, is a detail side vieiv (on alarger scale) of the center and one end ot the rolling mechanism shawn in Fig. l.; Fig.` 3 is a. plan view, and Fig'. et is an end` view, partly in section, of this same mechF anism; Figs. 5 and 6 are cross sectional` detail vievvs itself; Fig. 7 ai semi-diagrammatic side view (partly in` section) of the apparatus shown in Fig. l, as adapted to the production ot ivire glass.; Fig. 8 is a diagrammatic planl view ot' another form of reversibletable-multiplelehr` system which embodies the broad features ot my invention Fig. 9 is a semi-diagrainmatic side View (ron an enlarged scale) of the sheet forming mech anism oi this second term ot apparsi Fig. l0 isV a plan vieyv'oli another apparatus ivhich is designed. andy adapted for 'the prrr ducticn et; pressedplate products-or tor the joint and concurrent production oh hoth plain rolled and rolledfpressedr products-iu accordance with my improved;mode ot procedure; Figs. 11` and 12 are respectively side andv end elevations of' the mechanism shown in plan vieu in. Fig;` 110:51 Fig. lf3-is an end viewcf one portion et' this mechanism; Fig. let is a cross sectional elevation (on an enlarged scale) ot' the centrall portion of the apparatus illustrated in Figs. l0 to 1.3; F is an end view @part ly in sect-ion and partly in elevation.) o t' a. part of the mechanism shown in` Fig. 14;l and Fig. 16 is a detailedI sectional view` oli another part ot this same mechanism.

F ig. l? is a semidiagrammatic plan view. ot still another apparatus which presents a (in: elevation) of therolling table CII combination of structural and operative features that constitute a conjoint embodiment of my present improvements and the invention of my hereinbefore mentioned application Ser. No. 802,311, filed Nov. 21st, 1913; Fig. 18 is a semi-diagrammatic elevation (in part section) of this same apparatus; Fig. 19 is an enlarged detail sectional elevation of a portion of the rolling table mechanism shown diagrammatically in Figs. 17 and 18; Figs. 2O and 21 are diagrammatic plan views of two more arrangements of rolling-heating-pressing instrumentalities in combination with a reversible-table-multiple-lehr-system, and constituting, as a whole, further illustra-tive conjoint embodiments of the two inventions above referred to; and Figs. 22, 23 and 211 are enlarged detail views of a portion of t-he table mechanism that may be used in the apparatus shown in Figs. 20 and Q1.

In all of these illustrations the same letters and numerals are used, as far as possible, to designate and indicate the same, or corresponding, parts and elements of the various structural embodiments of my invention.

Referring first to the apparatus shown in Figs. 1 to 6: rlhis apparatus is designed particularly to produce rolled sheet products-either plain or figured or wire skylight glass-of an approximate size of 42 by 132 inches or less. In these figures, A, designates the glass furnace or receptacle containing the supply of unformed molten material; and B designates the system of tracks leading from this source of supply to the sheet forming mechanism C. This sheet forming mechanism is positioned symmetrically between two multiple lehr systems F and G; each of which comprises the sheet receiving chamber a, the series of connected annealing chambers or ovens --c-cl-e, and b-c--rZ-e, and the usual double rod Tondeur lehr 'tunnels f and f.

The sheet forming mechanism C comprises a spreading roll 1 adjustably mounted in vertical housings 2, 2, at the center of the machine and a twin faced rolling table 3 rotatably mounted, on end trunnions, Ll, 4, in a traveling cradle frame 5, that is movable longitudinally-under the spreading roll 1 to either the full line position D, or the dotted line position E, of Fig. 1. The table 3 is provided with a series of longitudinal passage ways, G, 6, 6, through which an intermittent circulation of water is maintained by means of the pipe and valve system illustrated in detail in Fig. -which will be more fully described hereafter-the arrangement being such that when the table is in position D the water flows through the passages, 6, 6, 6, from left to right, (i. e., enters at the left hand end and leaves at the right hand end of the table 3), and when the table is in position E the direction of circulation is reversed, i. e., from right to left.

In the operation of this apparatus the table is moved, say from the full line position D, until its right hand end is just under the spreading roll 1. A charge of glass, just sufficientin amount to make one sheet, is then taken from the furnace or source of supply A-which may be either a continuous tank or an individual pot melting furnace-transferred to the sheet forming` mechanism C by means of the track system B, and teemed or poured on the right hand end of the table fl just in front, or to thc left, ot the spreading roll 1. The table is then moved to the right under the roll-- the latter being simultaneously revolved in a counter-clockwise direction at a peripheral speed just equal to the linear movement of the table-by any suitable mechanism (alternative forms of which are later described more in detail) and the unformed mass of plastic glass is spread out into sheet form. The movement of the table is continued until it reaches the position E, at which time a current of water is automatically established through the passage ways tl, 6, etc., from right to left. The freshly rolled sheet is left in position on the table for a short interval-to give it a slight partial cset that will permit it to be moved endwise as a wholeand is then shoved into the receiving chamber, a, of the right hand lehr system G. The rst formed or cold portion of this sheet is obviously at the right hand end of the table-which received the mass of unformed molten material-and this portion will enter the lehr chamber first and will rest at the rear or hotter end of the said chamber. The heat communicated to the rolling` table from the glass, in the teeming and spreading operations, will expand the upper face of that table and lause it to bow or bend upward so as to present a conn veX upper surface and a correspomlingly concave lower surface. This expansion and bowing will be greatest at the right hand end which receives the entire mass el un formed molten material and which absorbs the greatest amount of h eat both from this mass as a whole and from the sheet subsequently formed therefrom. When the current of water is established through the table from right to left the hotter portions of the metal are first subjected to the influence of the entering fluid, and are obviously cooled most rapidly by this action, which tends therefore to equalize the temperature longitudinally of the table, and produce a more symmetrical convexity of its upper surface.

After the sheet of glass has been transferred from the table to the chamber, a, of the lehr system G, the table 3 is reversed or turned over on its trunnion supports, et, l,

lll() so as to bring' the cooler concared srrtace Ul.)DCriuost aud 1he hotter convex surilace underneath. liter this rerersal the tu-rthcr ou" the latter ifsuriface will ol cours@ loss rapidly than hetore 'beca ,-1 cooling` oi that suritace hy convection :urrents will he largely lolin'iinfted. of table reversal will he dctorniiued and controlllul to some extent hy the coolingrouditions--such as the teniperatlue and roluule ol" the cz flatinn unten the temperature o'l tht,` surrounding air, the radiation "lautern, etc. etc.-a1id can iu general he so chosen that when the time arrives 'tor the 'formation of the next sheet the upper rollj surface will still he slightly concur-cfi advancing end is ust under the .spa roll; a new charge ot n'lolten g tenured7 on that eild oit the taulen the right ol the roll; and this lnass is rolled out into .sheet torni as loe-fore hythe sul e quent movement oit the tahle (and rin'iultaneous clockwise revolution oil the r ,il l) to the right into position D; in which position a current of Water is automatically en tahlished through the passar is (t lt trom left to right. The sheet thus *tf next shoved into the reci-avion' chauiher. u, of the lehr system F; the cold end of? this short; hein@ as hetero, pushed to the haelt oud ot this chamber. L'

The heating' of me upper side ot the ta'hlc in the last descr ed @aeration raises the temperature ot the top :fini-tace ahore that ol the continually coollower face, `and l ons the zghtly concave upper su Y sl ightly convex-th e greater it); heine now at the left hand end of" the tahle-and the previously used slightly conrez; side lecornes slightly concave. The tahle is then reversed again, and is ready 'tor a repetition of the first described operation oit rolling; out a sheet 'from right to lett. ln the interim the sheet previously pushed into the first chamber, e, of the lehr system (l is moved laterally into either he chamber 7) or the chamber o oft this system, leaving); the receiving oyen ready for the reception ot the nent 'formed plate.

,ls the sheet rolling; operations prim-eed in the order dcscribed-the nuit`4 fined molten n'iasses being rolled out alternately in opposite directions and ou opposite sides o?? the tahle and then pushed in reciprocating; order into the receiving chambers ot the multiple lehr systems G and F (with the cold end ot each sheet always in adVance)-the sheets previously :termed and delivered to the first ovens or stations, G), and, fatF), are pushed successively into and through the succeeding' lehr chambers in the order MG), MF), l/(G), .f/(F), ctt?) etc.` (or vvice versare-may he desired) ,j so that each sheet liti() rests .in each receiving` clurlnher7 u, tor approximately twice the inteiw'al hrtu'ceu successive rollingv operations, and rests in each sucoeeding` lehr oren or (i, ,ie'tc., tor appi'oximately tour times this interval. Ur 4put iu the rorerse Way the frol'linggoperations may7 in vluy improved inode ol' procedure. he cai tried on with apin'miruately tour times `the rapidity heretofore iposriihle and pern'iissihle with the `usual arrangement ot rolliingY trhlo and lehr; and the rolling' gang may he kept continually occupied instead of heini; lieipt in cnliorced idleness `for something .like 80% of the Workingv time. ln addition to this Very lgreat `reduction in the cost ol manufacture-due to the ,greatly multiplied out put ot each rolling;` mechanism and cach group ol operators there'tor-the practise ol my invention hajs other very inarlnd advantages, in reducing ythe `physical strain and `Wear on the rolling' table faces and other cooperating` parts of the spreading `mechanism (hy synnnetrizino` the hee-tine` and cooling of different portions thereof in 'the manner previously described) thus maintaining these faces `much inore nearly llat and in inuch hotter surface condition than is possi- `hle when all the sheets are rolled out in the same direction and on the saine side ol' the table; and in correspondingly reducing the initial warping' and thermal distortion, vand improying the surface character and physical uniformity ol the final annealed product. These last advantages are as already indicated, particularly important ones in the manufacture of `ornarnental or iigured glass that may he produced either hy the use 'ol' figured surfaces, on the rolling` talole 8, (in the forms of apparatus shown in Figs. 14)) or hy the use-'ot a pressing` die subsequently applied to the rolled. out plates (seo Figs. 1 0-1G).

Taking` up nony a more detailed description ot the structural features ot the rolling mechanism shown in Figs. 2-(3, I first call attention to the construction oit the rolling-,r table 3. In the manufacture ot ordinary rough rolled plate-Which is used either in its rough state for skylight puposes, or is subsequently ground and polished to torni either semi-plate or 'lull plate glass-tlm smoothness, or rather elearness parencym ol the tahle side ot' the l oit prime importance-end in sin table l may he made in one piece (i ,l water iliassages 5, (l, {u} cored out)-the pl lacing' prelorahly cast on edge so that t metal on the two sides will he suhsta, V the saine in homogeneity and uniformity grain. But Where it is desired to produce rolled sheet glass the tahle surfaces olE which shall he of the highest quality` it is necessary to raalte the rolling laces oit the tahle ot Very 'tine close grained 'inetal that can he highly polished-preferably ,from the so of o llO

called soft chill iron that is in common use by thel manufacturers of glass molds. This iron can only be chilled on one side of the casting, and in order to produce a rolling` table with two chilled metal sides (and for other structural reasons) I prefer to malte this part of my improved rolling mechanism` from two plates which are planed and finished on both sides and edges and are then clamped rigidly together, to form a substantially integral piece, by means of the recessed cap-bolts, 7, 7, etc., and the rabbeted edge and end strips 8 8, 9 9, that are secured in place by the screws 10 10, etc., 11 11, etc. In order to obtain a very intimate physical union between the parts, the engaging edges of the rabbets and tongues, on the strips 8 9 and the table 3, are slightly beveled; and the strips, as well as the securing bolts 7 10 11, are heated before being put in place the subsequent contraction of the screws acting to bind the assembled portions of the table into one piece that will expand and contract and bend or bow like an integral solid piece of metal. The heads of the screws` 7, 7, are then covered by plugs of chilled metal-driven in cold when the table is hot and the surface containing these plugs is finished and polished to form one of the two twin rolling surfaces.

The end strips 9 9 are each provided with a trunnion projection 4, on which the table is reversibly supported in the cradle frame 5. These trunnions are bored axially to receive the water circulation pipe 12 which passes loosely through an opening in the center of the table 3 and extends the entire length of the machine (as shown in Fig. 1), being supported at each end by a set of inlet and discharge pipe connections 13, 14 (only one of which is shown` at the left hand end, in Figs. 2, 3, and 5). This circulation pipe is closed at the center by a. plug 15 (Fig. 5), and is provided at each end with a short section of smaller pipe 16, which is connected at its outer end with the discharge pipe 14, and carries at its inner end a ring or coliar 17, that serves to form the end wall of an annnlar chamber 18 between the pipes 12 and 16. This annular chamber communicates with the inlet pipe 13 through an ordinary T connection 19, and is provided at its inner end with a port 20. The inlet pipe 18 is l furnished with a valve 22 which is normally closed by a spring 23, and is opened by the engagement of the trunnion end with a slide 24 that is connected by a link 25 with the actuating arm of the valve 22.

Each end of the table 3 is provided with a transverse recess 21, which is covered by the end plate 9, and which communicates with the parallel longitudinal passages 6, 6, 6 etc. iilhen the table is vmoved te either of its end positions D or E the valve 22, at that end, is opened byK the engagement of the trunnion 4 with the slide 24; and as soon the port 20 is brought intoregistry with any part of the recess 21, water flows through the annular chamber' 18 and the port and recess, into and through the longitudinal passage ways 6, 6, etc. to the recess 21 at the opposite end of the table the end nearest the center of the machine-and thence through the other end port 20 into the pipe 12, from which it is discharged through the pipe 16 into the outlet connection 14. ln both positions water flows into the table at the outer and hotter end which is the end on which the glass of the last formed sheet was teemed and is discharged from the table into the pipe 12 at the inner and cooler end where the formation of that sheet was completed. frs soon as the table is moved from either of its end positions towards the other in the formation of the next sheet the flow of water through the table is shut olf by the movement of the ports 20 and 20 out of registry with the recesses 21, 21; and the valve 22 is then closed, by the disengagement of the collar 24 and the action of the spring 23, so as to prevent any escape of water from the exposed port opening 20. in the longitudinal movement of the table from one position of rest to the other, the end recesses 21 thereof will be momentarily in communication with the exit ports 20 at two points of the travel-one near the beginning` and one near the end of the table movement before the inlet port 20 registers with the outermost of said recesses; and these intermediate momentary communications of the water passages in the table with the outlet or exhaust pipe openings', aii'ords an opportunity for thc relief of any pressure that may be generated in the said pa. sages by the heating of the water therein during the tee-ming and rolling steps of the operation.

The cradle frame 5, which carries the reversible rolling table, can also be cast in one piece, but for convenience of machining it is preferably constructed of twoside bars 26 united at the ends by cross frames 27 which support the table trunnions 4, 4. The upper edges of these .side bars are provided with rack teeth which, are engaged bv the pinions 26. 28, that are carried on shafts rotatably mounted in boxes secured te the vertical housings of the machine, and are rotated synchronously by the spur gears Si) 31, Flo ll and the power driven shaft 32. rlhe cradle frame 5 is supported for longi-v tudinal movement under the driving action of the rack and spur gear connccticns on the series of track wheels 29, 29 etc, which are preferably mounted for independent adjustment (for the purpose of accurate align ment) in a corresponding series of hollow box frames 33, 33 etc. that are bolted to the ive Ill.)

lill

longitudinal channelboxgirders 34,34; and these glrdersare framed vtogetherat themen- `ter and ends, by the cross beams 35-35 and the bruising support 36, ito ,torni the mitin 'base of 'theiroilling machine drame.

italblr 'is in au .intermediate aosi'tion :under the spreading: roll); and the bloeks ,and spretuling roll vare elastieally suspended lon rods and sprii l2-lill Whieh are so adjusted as to 'Corry ytheinaxinfnnn portion of the Weight off these suspended parts, aand prevent their "downward `vmovement when the table ribs ell, 41, 4are not in engagement with the slotted blocks 39, One of the projecting ends orf the eccentric gudgeons Bh carries a slotted hub iplate de, which is iiuovided Vwith a llever or handle 45, anda clamp screw 4G, by -nleans of which the roll shaft 37 ran be rotated to. and damped in, any `desired position; 'thereby Vvarying .the vertical setting of the roll l `with respect Vto the L frames Si) and the rolling table 3. lThe spreading' roll itself is rotated 'on fthe roll shalt 3T by `ineens ol chain gjlveaiian'g.y which eonsist of sprocket Vwheels 4f( secured to the ends ofi the roll l, sprocket pi-ni'ons 48 secured to the ruoli (lr 'sind iiiri'ons 28, and sprocket chains which ermneet the said Wheels; the ratio o'l the sprocket Wheels and pinions being such that the roll l isrevolved at a peripheral speed equal to the linea-r movement of the labile B. Take up pinions ll, 50, laterally mow-ble on the housing standards 2, 2. are provided for the pur pose oli adjusting the tension of the chains when the roll is raise-d or lowered in the manner above described.

The purpose of providing the sliding connertions between the roll. frames 39 and the table ribs 4l is to maintain a. uniiorni spaeiirir lietweeii the roll il and thetable 3 duringr the sheet iin-ming ojwrutions. regard l olf an" longitudinal eurvatiufe olA the table, or any other vertral inm'einents of either edge tlufreol: and to also provide means lor the operative niaintenanee of any desired vertical. relationship between these parts so as to produce sheets of glass of any predeten inin ed thickness. This thickness can bereadil y Yaried-between each successive rolling4 operation if desired-by a movement oit the handle 45.

In order to facilitate the reversal of the rolling: table 213 the end trunnion supports 9T may be provided 'with ball. bearing anti- :friction rolls 5l Fig. t; :and seine simple fand easily operated means-such as the sliding pins Y52, (see Fig. 2)-is also provided to prevent suoli `reversal yor aecidentwl rotation at the ltimes when 'the ribs llll faire :not in iengageinent with the blocks l :also :provide a pair et triangullaar guns 53-irliieli may be plaeed in either llhe lullll line or the dottedline position sliouui liu ll' and. sup-ported 'in that position iby `any suitable means (such as `the Alioo'ks 5dor b-betu'een which the glass tecnici-,limon the table in iront of the spreadiing roll. These fguns are of 'the usual well known forni and in order to avoid i-mneressary complexity of the relatively small. sra-le A'illustra'ti'oifis they are fno't showin 1in either Figs. or (11. rThe prime :mover `which drives the shalltl, `as well :as various other misnor details olf construction (necessary `lier the coni'fenient commercial `opera- Ation of the apparatus, but forming nnopart of `my present improvement@ are likewise omitted fon the drawings as they `aan be `readily supplied by any skilled engineer.

The rolling mechanism above described is suitable for lthe production of rolled sheets Vorf any desi/red thickness fand 'having either plain or figured sur-races on yorne Lor lboth surfaces; and 'it is furthermore `of such construction that either `the "table or ythe spreading roll, or both, may be very readily .renioved and replaced by others (in hangin-g Ltroni ornamental or prism glass manufacture to plain skylight glass, `or vice versa) and it also obvious that the twin faced rolling table 'may be provided with one fiat rolling Asurface 'and one figured ,rolling sinfare so as to i-pivo'duee fboth liorins olf sheet product eonourrently.

The above described :torni of sheet lerining Aapparaltus :an also be utilized in the production of Wire glass bythe two sheet or sandwich method by adding to the meol'ianisni shown in Figs. l to 6 the Wire carrying rolls 'and `chutes 56 and 57 shown in Fig. T. In the manufacture of this last mentioned product the table is started say Jfrom `position E and the lower sheet is rolled out by moving:` it to the left ilrnder the sprezuflngr roll l. The Wire uiesh is then drawn down the obute 5G until its end rests on the glass; a non' ladle ol vmolten nia` terial teeniedl on l.: end of the .lirst 'formed sheet and rolled out on top of the latter-and the iul'eri'iosed Wire 'nieshby the reversed movement olf the table to 'the right, back to position l. In the interval between the rolling' of the lower and upper sheets `the roll l is.I of eourse, raised vby the lever 45 to the height necessary to form the second layer on top of the first; and in this procedure it is desirable to provide sonie simple Ytorni of stop and lock 'rnee'ha- 'nism which will arrest and hold the `ee- Eno centric gudgeon shifting device at the two points required for the proper rolling of the two layers that together form the completed sheet of wire glass. The chute 56 is next raised and the table is preferably returned to position D from which the now partially chilled and set plate is shoved into the receiving chamber of the left hand lehr system F, with the first formed end of the. lower layer---which is obviously the coldest part of the completed sheet-in advance, or toward the inner and hotter part of the annealing chambers. The table is then reversed-while it is being cooled as before described byareversed water circulation--the spreading roll is lowered to its lirst setting, and the chute 57 is dropped to its delivery position; and then, after the proper interval, the next double layer sheet rolling operation is carried out-each layer of this sheet being spread in the reverse direction to that in which the corresponding layer of the preceding sheet was spreadand the completed plate is shoved into the receiving chamber of the right hand lehr system G.

It will be clear that the last described mode of procedure in the manufacture of two layer wire glass-or any other multiple sheet glass product-by the use of the apparatus shown in Figs. 2 to 7, presents substantially the same advantages as are generally characteristic of my improvements as applied to the production of single layer sheet or plate glass.

Figs. 8 and 9 show another form of apparatus adapted to the practise of my invention. In this arrangement of instrumentalities I make use of a longitudinally fixed reversible rolling table 3, which is mounted directly on stationary trunnion supports 27, 27a at the ends of the machine frame 34C, and of a longitudinally movable roll l", that can be drawn over the table-alternately in opposite directionsby means of endless cables, 60, 60, the ends of which are secured to draft eyes 6l, 6l, rotatably mounted on the ends of the roll shaft, and the centers of which are wrapped around the driving drums 62, 62, that are driven synchronously by any suitable motorunder the control of the machine operator.

llach of the trunnion supporting standards it the machine frame 34' is provided with a pair of roll guides 63, 63, which are so formed and arranged as to engage loose collars or rollers rotatably mounted on the projecting ends of the roll shaft (between the ends of the roll la and the draft eyes 61, 61) and lift the said roll la above the level of the rolled out sheet as it passes beyond either end of the rolling table 81. These end standards also carry tight-and-loose cable control devices-such as the swinging lever sheave supports, 641, 64,-v-which may be readily and conveniently manipulated so as to slack away and drop the upper portions of the cables 60, 60, below the level of the rolling surface (as indicated in full lines in Fig. 9) or so as to lift and tighten these cables (as indicates in dotted lines in that ligure) when the spreading roll is to be moved in either direction.

The table 8a is of the saine general construct-ion as the one used in the previously described form of apparatus and is supplied with cooling water through pipes 65, 66, that lead from the end trunnions to a fourway valve 67 located near the driving drum 62 and adapted to be automatically operated by a gear 68 which is connected to the drum 62 in such manner as to reverse the valve at the completion of each longitudinal movement of the spreading roll la;

rIhe sheet forming mechanism as a whole is positioned as before between two lehrs F and Gr, which consist in this case of only one set of chambers, c, o, c, cl, e, communieating at the end with the rod delivery chamber f. The ladle, or pot, track system B is arranged to permit of the teeming of the glass at either end of the stationary rolling table-a single pair of triangular reversible guns 69 being provided for confining the glass laterally during the teeming and rolling operations. The thickness of the sheets produced by this apparatus is determined either by trangs 70, 70, secured to the two sides of the table 3a, or by roll collars carried by the ends Of the spreading roll la; and the roll is rotated as it moves along the table either by the frictional contact between its surface and the trangs, or by thev engagement of the toothed collars with rack teeth on the edges to the table. These last mentioned alternative details of construction are all well known, and in common use, and are not therefore specifically illustrated.

The operation of the apparatus last described is as follows: Starting` with the roll l at the left hand end of the table-with all the parts in the full line position of Figs, 8 and 9-the drums 62 are rst rotated counterclockwise to lower the spreadingv roll onto the left hand end of the table 3a; and the guns 70 are placed in position in front of the roll (as shown in dotted lines at the left of Fig. 9). A. charge of molten is then teemed on the table (between the guns and in front of the roll), and 'the right hand sheaie levers 6-lV are thrown up to the dotted line position, to raise and tighten the upper right hand portions of the cables 60. The roll la is then drawn forward over the table surface by the counterclockwise rotation of the drums GQ-thus s} neacling out the unformed mass of glass into a sheet of the predetermined thickness*until it reaches the right hand end of the machine iframe Where it i.' Pfain litted tromv the tahlethe enpu, e...eV 3 ot the collars at thel ends ot the roll shalt with the .right hand guides G3. Sit the end ot this increment lthe gear t8 engages with the handle ot the tour-us. valve (ST and moves the said valve in such direction as to admit Vvater to the lett hand end oit' the tahle-throu h the pipe and allow it to escape troni the right hand end thereof (tlirough the pipe The sheet. utter havingr become suiiiciently set. is then shoved into the lett hand lehr F -with the cold end l'orernost. The tahle next reverse-d on its trunnion supports and the lett hand sheave levers (34 are thrown down to lower the cables loelou' the tahle surface and thus prevent them 'from interteringwith the next glass teeming operation. The parts are now in position tor a repetition of the previously described sequence ot steps, with a reversed order ot movement ot the spreading roll trom ri gght to leit,-\vith a terminal reversal of the tour-way valve 67 to admit water through the pipe (SG and discharge it trom the pipe (lf3-und with a Subsequent delivery ot the. next termed sheet to the right hand lehr G.

Figs. 10 to 1G inclusive illustrate a toi-m ot apparatus adapted to produce pressed plate products oi" an approximate size of l2 hy 9G inches or less-hy my improved sheet forming process. In these figures 3b indicates the rolling table Which is similar to the table shown in Figs. and G in that it comprises tivo plate sections secured together loy the side and end strips El, 9, and the bolts 7b, 10b, 11b (see Figs. 14 and 15) and is provided with longitudinal and transverse Water ducts 6b, 2lb, which communicate with inlet and outlet passa; in the hollow trunnions 4. 4". ou the end strips 9. The edges of the side strips tl are prorif :d with i .ck teeth which are engaged, in the different longi fi. positions olf the tahle, hy one (or tuo) et the three pairs oit pinions 28a 2S" and 28C. that are driven synchronously hy the attached Worm Wheels 30?, 30h, 30C. and the interconnected system ot Worms and Worm shafts 31"-31b and hevel gears and cross shaft 3.2lg--the driving Irear system as a Whole being,T actuated hy a reversible variahle speed motor T2, and controlled hy suitahle rheostat and switch mechanism (not shown). The talole 3" rests directly on a. series ot track wheels b, 29h, etc., (six ol." ivhich are secured to.y and revolve with, the pinions and Worin gears 28"'-2502 28"20 and 2SC-30C, and the remuiuder ot which act independently) ro tat-ably mounted in the hollow hex 'iframes 33h 33", etc., that are separately supported (for independent adjustment) on the longitudinal channel hoX girders 34h; und these side girders are trained together, at their ends and at intermediate points .in their` length, hy the l' ur sets of cross ,igirdcrs 35h.) $151", etc.` (shown in Figs. 10, 11, 13 and 14)7 and' the housing` supports and cross beams Sil, etc. (heet shown in. Figs. 11 and 14) to term a rigid and unitaryv hase for the entire rollinpfpressing mechanism. i

The machine trame is provided at its center with two symmetrically disposed liousirc' standards 2" 2b, which serve to support hoth the spreading rolls 1b and 1C, and the pressing' die 73, which is used to refigure or resurtace the upper tace ot the glass sheet after it has heen rolled out on the table 3b. The spreading rolls l and l are each rotatably mounted on a shaft 3T", which is secured at its ends to the extremities ot the levers 74, A74, that are pivota-lly mounted at their central points on the housing' standards 2". rllhe ends ot these levers 7 4 are provided with cross guides that carry adjustable plates 39, 39, (shown in Figs. 11, 14 and 15, hut omitted in Figs. l() and 12) which are slotted at their lower ends to engage With the rihs 41h, 41, on the edges of the table (as best shown at the right ot Fig. 15). These plates 39", 39C, also carry stud bolts 75, 76, which serve the `ioint purpose ci? clamping the plates in the cross guides and et' rotatably support-ing the single spur pinions 'i7 and the double spur pinions M' t (n. The larger ot the tivo gear elements ot these double pinions engage the pinions 77, and the smaller gear elements thereof engage the spur gears 47D 47 hest Figs. 14 and 15) which are secured to the ends of the rolls 1b and 1C. lhen either of these rolls is lowered` into operative position (in which the slotted ends ot the plates 39 or 39 engage the side rihs 41") the spur gears 77 are engaged hy the rack teeth on the upper edgres ot the side hars, il, and rotate the roll at a peripheral speed just equal to the linear movement of the table surface.

The press die 7?; is suspended from the structural steel tunic T8 hy means of sie; hans/gers 79, 79 etc. iviich engage at their lower ends with pins 80, 80, etc., that are threaded into the ends ot the die plate 73, and which are secured at their upper ends to the pistons 81, S1, etc., in the pneumatic cylinders 82, 82, etc., that are bolted to the ends of the trame 78. rllhis frame is in turn piif'otally suspended on the heavy cross shalt 83 that is carried by the housing,r standards 2", 2". The cylinders 82 are all similar in construction, hut the tour at the corners oit the trame i8 are oit larger diameter (see cross section ot Fig. 16) than the intermediate ones (see cross section at the right ot Fig. 14) 5 and these four larger cylinders are `interconnected loy the system of equalizine` conduits 84, 84, etc. Each cylinder is also provided with an entry port which is so positioned. as to he slightly open when the pistons 81 are in their lowermost position, and to be partially opened, into the space below the said pistons, when the latter are raised to the top of the cylinder. These ports are all connected to the system of air supply pipes 8G, 86, etc., which is in turn connected to the air conduit 8T lthat leads to a main service pipe 88.

Springs 89 are preferably interposed between the pistons and the tops of the cylinders, but these springs are not necessary and may be omitted. l also prefer to provide two additional cylinders 90, 90, which are secured to the frame 78 just underneath the cross shafts 83, and which carry spring pressed pistons similar to those shown in section at the right of Fig. 14, but which are not connected to the air supply system 86-87-88. The ends of the piston rods of v these cylinders bear on the back of the die 73 but are not pivotally connected thereto (see Fig. 14).

In order to make use of the pressing die 73-in reiiguring the rolled glass plate-l preferably employ the cylinder-lever-system shown in Fig. 14C for lifting the table from its supporting' track wheels (after it has been brought to the center of the machine) and pressing the glass sheet supported thereon against the lower face of the die. This cylinder-lever-table lifting mechanism is the same, in all essential respects, as the corresponding portion of the apparatus illustrated and described in my earlier Patent No. 789,397 and need not therefore be again explained in detail here. The single acting cylinder 91, which actuates the table lifting system, is supplied with air-through the pipe 92, that is connected to the main service pipe 88; and the admission and discharge of compressed fluid, to and from the cylinder 91 is controlled by a three-way valve 93 in the pipe 92.

In order to provide for the reversal of the rolling table 3b the machine frame is provided at one or both ends with a pair of vertically movable standards 94; that slide in frames 95 and can be raised and lowered. together bv the screws 96 and the connecting worm and worm wheel gearing 97-98 which is actuated by the motor 99. By the action of this lifting mechanism the table can be raised enough above the supporting` track wheels 29b to permit of its reversal (see Fi'g 13).

T he lifting of the table at the pressing station and also at the reversing station (or stations, if two are used) prohibits the employment of the automatic water supply system used in conjunction with the apparatus of Figs. 1 to 7. In place thereof l provide an equivalent automatically controlled system which comprises the water supply pipes 13b, 13"` the discharge pipes 14h 141-1, and the valve mechanism shown in section at the left of Fig. 14h This valve mechanism consists of a combination sleeve and plug checlt valve 100 which is iitted to each of the hollow trunnions 4b 11b and a sliding gate valve 22b which vis mounted on the upper end of each of the standards 94, and is normally held in elevated (and closed) position by a spring 23h. Each of the standards 94- is also provided with a pipe 101 which communicates with the opening in the cover plate of the gate valve 22", and is slidably fitted in the vertical portions of the supply and discharge pipes 13b-11i".

The mode of action of the above described water control system is simple and easily understood. l"Vhen the table is being moved the standards 94. are all lowered to their full line positions shown in Figs. 11 and 14 and all of the parts connected thereto are below the level of the supporting plane of the track wheels 29h. )When the table has been brought to either of its end positions D or E the trunnions 4b are exactly, or approximately, above the Y supports on the ends of the adjacent standards 94. lVhen these are raised the beveled inner edges of one or the other of these standards rst engages the contiguous edge of one of the end strips 9b and moves the table slightly one way or the other until it is exactly centered between the standards (this slight movement being permitted by the back lash or clearance of the spur and worm gears 28a-30, etc.) The continued upward movement of the standards next brings the faces of the beve-led grooves 102, on the ends of the gate valves 22h, into engagement with the coned ends of the sleeve valves 100, and presses them back suliiciently to simultaneously open the central plug closed port and the peripheral sleeve ports 201. Further upward movement depresses the gate valves 22b against the tension of the springs 23b-this movement being made positive by the engagement of the lugs 103 with the lower sides of the trunnions tbdand opens the ports leading to the pipes 101. The parts are so designed that, at this stage of the upward movement, the lower ends of the pipes 101 are lifted above the ends of the lateral branches of the pipes 13b, 14"; and the water now flows from the first of these pipes 13b up through the telescoping pipe 101, through the valve ports in the depressed gate valve 22h, and into the opened sleeve valve 100 at the outer, hotter end of the table; and is discharged, in a reverse flow through the corresponding valve system, at the inner end of the table, into the exit or exhaust pipe 14h. This flow continues as long as the standards are in lifting contact with the table trunnions-regardless of whether the table is elevated to the reversing position shown in Fig. 18 or is in the lowered position shown in Figs. ll and misi-iso l2-hut it is automaticelli,Y shut oil when the standerd are lowered out of liittf engsgeinent with the trunnions hy the Yjioi action of the rate valves :5291" und the tele scoping pipe lill. The thun i lowering inoveinent ot the stsndaros di gages the grooved ends l0?, ot the puits troni the coned ends of the tinnnion sleeve valves 100, and permits these rali/'es to he closed hy their springs therehy preventing the accidentel escape ot the water still remaining in the table cavities 2l" But these valves are so t the event of en excessive press erated in the said cai/ities thv the iie1 oiI the liquid therein dur' f and the rolling and pressing;A of erations) plug elenients at the ceiters ot the selves will he lii'fted troni their serts-agsinst tension of the closing` springs-to reir such excess pressuren The values le() therefore perform hoth the tunetions oft aux iliary control Valves and oi? safety rali' es; und the latter function. has heen tound to he a particularly inrportant one in roliing; and pressing thick sheets ot prisin dass The operation of this rolling-pressing); mechanism as a Whole is as follows: f ingl with the table in the dotted line position E shown at the right oit n ll e. with the other parts in the tull line posi tions ot Figs. 10 and ll, the tahle :is

step n inoved a short distance te the left until its end 1s under the roll 1c and the side rlof 411 have engaged with the right hund 1 ot' guides 39C-and a charge of glass is thei teenled on the table hetrteen the guns 53C. The movement of: tl e tahle to the lett is then resumed and continued until the glass spreading' operation has heen coinpleteth and the tahle has passed out troni under the roll l into its central position under the press die i3 (as shown in Figs. and lit)n 'llie three-way valve 93 is then opened to adniit compressed air to the rear end ot 'the cylins der 9i. This hitts the tehle and the sheet until lthe 'upper surface et the glass cornes in contact with the lower surtaee oi the press die 73. The latter surtaee at once adjusts itself` to parallelism With the usoer 'tace oit the sheet hy the rocking` ot Athe press traine 78 as a Whole, on the cross sluit-t` su port 83; and hy the further independent movements it necessary, ot the pistons 8l in the Cylinders rihe tsl/ile continine4 its upward movement, carryin with it the die and lifting' lthe pistons Sl against the pressure oit the air in the upper ends ot the cylinders S2. A very slight upward n1ovement ot these Apistons elose: 'the entri;r ports 85 and the air trapped shove the pistons is then uniformly coinpiessedmequalisstion ot the pressure on the ton ot the :tour asin pistons being ensured lo",v the pine system St-to exert, in conjunction with the springs which l i i ce Way vulve 93 is :menate 3o iarge tie nir troni 'the lo; lt ot the niais press pist( n 9 (and pern'iit ot ifrn oit i tl e cor nl -ssed air thus ade :over ends or the cylinders Si?, increment oit the die 73,

i il

the tulle to its ,loweri 'ef he to he grat l, and .irai troni the pres-sed l ad i Lt; suddeA ly separated tin, ein et tl, ie ot in tial Contact.

ie if ot the pressure at shan o) or reitigruring; ac-

This inon'ientar the end oit the tion, and the suhseque eiadnel i'iartingg or' `he t ass and die suiriaces, has heen tound to he oir great importance. sind adventriesD in 'the pressing operationn because ot the tendeinzr oit the hot grlass to stink to the die surnices; and it has required a very slrilltul manual manipulation oit 'the 'valves ot the press mechanism heretofore used to overcome this tendencia lli/'hen the table hss once inore heen lowered onto its supporting truck Wheels it is moved sgrain to the leit to the `tull line position, D, as shown in Figs. l0 and lil). The pressed sheet is then shoved troni the table into the ,ei ig chainhen (i of the lehr .sj/stein l; first 'Formed oit this sheet being` in ed rence., The standards 94; are then elevated l `they engage the truiniions l-b, and the valves l0() and 22h are sutoinaticall,v opened (as herore described) thus estaillishinar a ot w: ter through the tuhle d iets (5" in sains direetion es that in which 'the 1 rifas iirst spread At the proper time l raised to the position y j, andthe "aliile is reversed sind il again. hitter the proper coollns elapsed the standards @el iown out oi: engjegeinei i with the t. Y All) thereh;T automatically shutt'` t .m the 'lion7 ot Water through the t` his ene the spreadiinr roll lb is lowered until the gniuie g 39h in. position 'to engage the taole rihs fi-,lll Tl e parts are smaller size, and of greater p thickness than plain rolled sl and. because of theirl bei; g' thicker, an also relatively more chilled (by the pressing operation), they are more di'licult to anneal properly. ln consequence of this the length of time during which each plate inust "rest" in each annealing' charnber of the lehr is increased. The longer enforced cwait between each rolling-pressing performance (in the ordinary unidirectional operation of the unifaced-tablesingle-lchr combination heretofore employed), and the smaller superficial area of each plate produced (in the ordinary practise of this two step process) great-ly red ccs the output from each machine and correspondingly increases the cost to such an extent as to seriously limit the demand for this class of products. One of the above mentioned factors of increased cost-viz, the limitation in the size of the rolledpressed plates--can be eliminated by the use of the three step process of rolling-reheating-and-pressing,which is described and claimed in my copendingapplication Ser. No. 802,311; but the method there disclosed does not increase the speed of operation of the machine, i. e., it does not reduce the interval between the manufacture of successive sheets. But the use of the process and'apparatus herein described increases the output of each machine between three hundred and four hundred per cent; and both the labor cost and overhead expense of manufacture is thereby so greatly reduced as to make it possible to market these high grade pressed plate products at a price comparable with that now asked for ordinary rolled sheet glass. This is a very remarkable advance in this branch of the glass working art.

The bidirectional operation of the reversible-table-multiple-lehr combination also presents another important advantage in the manufacture of plates which are first rolled and then pressed (either with or without an intermediate reheating of the rolled surface). ln the ordinary manufacture of these products the wait between successive pressing operations is so prolongedfor the reasons just statedthat the pressing die must be maintained at the proper working` temperature by some extraneous heating` instrumentality. This is undesirable (although heretofore necessary) both because of the expense, and also because the heating means usually employed (on the score of convenience and economy) is a series of gas jets that are manually placed in position under the die after each pressing operation and taken away again just before the next rolling operation. lt is impossible to obtain in this way a uniform and symmetrical heating of all portions of the die surface and it is also impossible to avoid the oxydation and tarnishing of the pressing faces, which must be kept in a highly polished clean condi.- tion in order to obtain the best results. By the use of my present invention the interval between successive pressing operations is so greatly reduced that the die is maintained at the proper working temperature b v the heat impar ed to its from the glass alone; and all necessity for extraneous heating between such operations is completely' eliminated.

The successive or alternate spreading of the molten material in reversed direction, and on the opposite sides of the reversible two faced rolling table, and the intermediate internal cooling of the metal between these two rolling surfaces by successively reversed currents of cooling fluid-which results in the maintenance of substantially uniform average temperature conditions in different parts of the tableis also of particular importance and advantage in the successful pressing of rolled plates of large size, because it eliminates in large part the effects of the bowing or convexing of each table surface when the mass of intensely hot glass is tesmed and spread upon it; and thereby avoids the necessity of imparting a large compensatory or corrective concavity either to the table surface (with a corresponding longitudinal curvature to the roll surface-or to the die surface, or to both combined-as described in earlier Patent No. 952,890-which it has heretofore been necessary to do in order to obtain a satisfactory pressing or religuring action on any extended area of freshly rolled molten material. rfhis reducing` of the bowing effects-or rather the balancing of the alternately reversed bowing effects-on the twin rolling surfaces of the table, also eliminates the necessity for using the massive and cumbersome backing plate heretofore employed for holding the pressing die in mechanically adjusted or warped condition; and permits of the mounting of that die directly on its spring supports in the manner hereinbefore described, thereby reducing the cost of construction and simplifying the operation of mounting and dismounting this frequently changed element of the mechanism.

In the manufacture of pressed plates that are of the maximum size for which the apparatus shown in Figs. l016 is designed, and which are of unusual thickness (e. skylight or floor prism glass), or which are formed from material which has a relatively high thermal conductivity (e. g., baryta-lime-glass, etc.) the intermittent local heating of the rolling surface is much greater (and the resultant warping or bowing of that surface is correspondingly more upper surface-of one or both products being either plain and smooth (ifsemi-platei,

operations described in my earlier Patent No. 872,484; and is therefore capable of rapidly and economically manufacturing a number of composite plate products, that can only be produced at great cost, by theuse of a single table one lehr combination, because of the greatly extended period of annealing required for these large thick plaques of poorly conductive vitreous material.

My present improvements are also capable of being very effectively used in conjunction,

and in combination, with the invention disclosed in my pending application Ser. No. 802,311, which relates to the manufacture of pressed plate products in very large sizes. As pointed out in the last mentioned application the production of such plates by the two step rolling-pressing process has always been restricted and limited, in part by the diiiiculties of overcoming, or compensating for, the greatly magnified warping or bowing of very large tables, and in part by the difiiculties of maintaining all parts of large rolled sheets at the proper temperature for the subsequent pressing` operation (and also by various subsidiary constructional diiculties which pertain to the apparatus employed rather than to the mode of procedure). These difficulties are all overcome by the use of the three step rolling-heating-pressing process-and the apparatus designed for the practice thereof-which is illustrated and described in my aforesaid prior application; but the speed of operation that can be attained in the employment of the invention, as there described, is limited and determined by the necessary period of rest of the pressed sheets in each lehr chamber. This limitation is avoided by the extension or application of my present invention (involving the bidirectional operation of a reveisible-table-multiple-lehr system) to the three step rolling-heatingpressing process of my previous application g and one means by which this can be accomplished is shown more or less diagrammatically in Figs. 17 and 18, which will next be described as briefly as possible.

In the combination of instrumentalities illustrated in Fig. 17, preferably employ two double faced rolling tables 3 and 3e each of which is similar in construction to the tables shown in Figs. 6-14 and 15 (hereinbefore fully described) save that it is provided with side trunnions ad 4d which are rotatably mounted in the side bars of the open box frames 5d, 5e, so that when the table is reversed, side for side, it is simultaneously turned end for end. The table frames are provided with track wheels 29d, 29d, that roll on tracks 105, which are divided into five sections-two rolling station sections carried on the lateral or cross transfer carriages 106, 106, two stationary end sections extending into the reheating furnaces R1 and R2 and a stationary central section extending under the press mechanism F. The two transfer carriages 106, are mounted on track wheels that roll on cross tracks 107-107, so that the said carriages-and the rolling tables supported thereon-may be moved from the positions D or E to either of the positions D1 and D2, or El and E2 respectively; and in these positions, the tables are opposite the first chambers or ovens of the annealing lehr systems F1, G1 and F2, G2. The spreading rolls l, 1e, are revolvably mounted on stationary shafts that are supported for vertical adjustment-(either on eccentric end gudgeons as in the Figs. 1-5 construction, or on screw actuated housing blocks of the well known form commonly used in rolling mills, planers, etc-as indicated in Fig. 18) with respect to the rolling table supports; and the rolls and table frames can be actuated synchronously by means of two endless cables d 60d that are arranged, one on each side of the machine frame, and are moved at will in either direction by the connected driving drums 62d 62d. The pressing mechanism at the center of the machine comprises a fluid pressure cylinder 91, and a system of inter-coupled bell crank levers and links (the action of which has been fully described in my earlier Patent No. 789,397) that are connected to the die plate 7 3d through the medium of the spring suspension members 82d 82d, etc ;-the parts being normally maintained in the elevated full line positions of Fig. 18 by the counterweights 10s, los, etc.

rlhe adjustable roll shaft supports, cable sheaves and drums, and press mechanism as well as portions of the end sections and center sections of the tracks 10G-are carried on a rigid structural steel framework comprising the columns 2d, 2d, etc., the longitudinal girders 84d, and the cross beams 35d, that are so arranged as to permit of easy access to all operating elements of the sheet forming mechanism, and to permit of the ready removal and replacement of the spreading rolls, or of the rolling tables, or of the press die or dies.

rFlic reheating furnaces R1 R2 are of the same general construction as that shown in Figs. 10 and 11 of my copending application 

